1. Field of the Invention
The present invention relates to novel benzyl alcohol compositions for stripping coatings such as paint coatings from high strength steel surfaces such as cadmium-plated steel, or from assemblies containing high strength steel components such as aircraft surfaces containing high strength steel fasteners, while minimizing the effects of corrosion or hydrogen-induced embrittlement normally caused by the action of benzyl alcohol formulations on such steel surfaces.
2. State of the Art
Water-based benzyl alcohol paint stripping compositions have been developed as substitutes for methylene chloride-based paint strippers which were highly effective for their intended purpose but have been found to be hazardous air pollutants and potential human carcinogens due to the presence of methylene chloride. Reference is made to U.S. Pat. Nos. 4,732,695 and 5,454,985 for their disclosure of non-hazardous, low cost, effective aqueous paint stripping compositions based upon benzyl alcohol, and the advantages of such compositions over prior-known organic solvent compositions.
While such aqueous benzyl alcohol stripping compositions are very effective for their intended purposes, it has been found that they can cause hydrogen embrittlement and hydrogen-induced cracking of high strength steel such as but not limited to, AISI 4340 and 300M, and Aer Met.RTM. 100 alloy, which can be cadmium plated or ion vapor deposited with aluminum, or otherwise coated. It is well known that structural steel, normally designed to be heat-treated above 180 ksi, can be subject to hydrogen induced embrittlement, hydrogen induced cracking as well as corrosion induced by the environment, particularly after treatment with conventional benzyl alcohol paint stripping compositions.
Aqueous aromatic acid compositions are also known for removing flux/contamination from printed circuit boards, and reference is made to U.S. Pat. No. 5,431,739 which discloses such compositions containing various additives including corrosion inhibitors for the solder and other materials on the printed circuit boards.